请教射频校准PA Gain (1299) ping/pong effect detected问题

今日有两片主板一直修不好,GSM校准已经OK，WCDMA的RX也过了，就差APC了。校准提示如下：
WCDMA APC calibration：PA-gain calibration ping-pong detected
因很少见到这种错误，所以发出来大家讨论一下到底是什么原因导致的。
检查了如下关键参数：
PA input=6dBm
PA EN=1.8V
VCC1=VBAT=3.8V
VCC2=3.4V~3.5V
PA output=26dBm(ANT端口测试)
单从现象上看，是PA的输出功率太高了，而且很难降下来。
我等会再检查一下PA的其他控制电压是否正常...
校准log如下：
2015/03/25 11:22:36.859 -------------- WCDMA APC (8-level DC2DC PA control) start --------------
2015/03/25 11:22:36.859 CWcdmaApcClass::ParseCalibrationConfig ()
2015/03/25 11:22:36.859 IWcdmaInterface::ParseWcdmaCalibrationConfig()
2015/03/25 11:22:36.921 ICalibrationInterface::RunCalibration: Write NVRAM intial value start
2015/03/25 11:22:36.921 CWcdmaApcClass::PopulateInitialValues()
2015/03/25 11:22:36.921 IWcdmaInterface::IsBandSupported() band(0), ui_band_support(80)
2015/03/25 11:22:36.921 IWcdmaInterface::IsBandSupported() band(1), ui_band_support(80)
2015/03/25 11:22:36.921 IWcdmaInterface::IsBandSupported() band(2), ui_band_support(80)
2015/03/25 11:22:36.921 IWcdmaInterface::IsBandSupported() band(3), ui_band_support(80)
2015/03/25 11:22:36.921 IWcdmaInterface::IsBandSupported() band(4), ui_band_support(80)
2015/03/25 11:22:36.921 IWcdmaInterface::IsBandSupported() band(5), ui_band_support(80)
2015/03/25 11:22:36.921 IWcdmaInterface::IsBandSupported() band(6), ui_band_support(80)
2015/03/25 11:22:36.921 IWcdmaInterface::IsBandSupported() band(7), ui_band_support(80)
2015/03/25 11:22:36.921 CWcdmaApcClass::ParseCompensationInitialValues() 7
2015/03/25 11:22:36.937 CWcdmaApcClass::ParsePaControlInitialValues() 7
2015/03/25 11:22:36.937 CWcdmaApcClass::GetPhaseComp() mode: 0
2015/03/25 11:22:36.937 CWcdmaApcClass::GetPhaseComp() mode: 0
2015/03/25 11:22:36.937 CWcdmaApcClass::GetPhaseComp() mode: 0
2015/03/25 11:22:36.937 IWcdmaCalibrationInterface::GetUeCapability()
2015/03/25 11:22:36.968 CWcdmaApcClass::GetVpaVoltagePairByStringValue()
2015/03/25 11:22:36.968 CWcdmaApcClass::GetVpaVoltageStringPairList()
2015/03/25 11:22:36.968 CWcdmaApcClass::QueryVpaVoltageListSupported() == 1
2015/03/25 11:22:36.984 CWcdmaApcClass::GetVpaVoltagePairByStringValue()
2015/03/25 11:22:36.984 CWcdmaApcClass::GetVpaVoltagePairByStringValue()
2015/03/25 11:22:36.984 CWcdmaApcClass::GetVpaVoltagePairByStringValue()
2015/03/25 11:22:36.984 CWcdmaApcClass::GetVpaVoltagePairByStringValue()
2015/03/25 11:22:36.984 CWcdmaApcClass::GetVpaVoltagePairByStringValue()
2015/03/25 11:22:36.984 CWcdmaApcClass::GetVpaVoltagePairByStringValue()
2015/03/25 11:22:36.984 CWcdmaApcClass::GetVpaVoltagePairByStringValue()
2015/03/25 11:22:36.984 CWcdmaApcClass::ZeroSubbandCompensation() 7
2015/03/25 11:22:36.984 CWcdmaApcClass::WriteNvramDataByBand() 7
2015/03/25 11:22:37.093 IWcdmaInterface::IsBandSupported() band(8), ui_band_support(80)
2015/03/25 11:22:37.093 IWcdmaInterface::IsBandSupported() band(9), ui_band_support(80)
2015/03/25 11:22:37.093 ICalibrationInterface::RunCalibration: Write NVRAM intial value end
2015/03/25 11:22:37.093 CWcdmaApcClass::StartCalibration()
2015/03/25 11:22:37.093 CWcdmaApcClass::UpdateVpaVoltageStringPairList()
2015/03/25 11:22:37.093 CWcdmaApcClass::GetVpaVoltageStringPairList()
2015/03/25 11:22:37.109 CWcdmaApcClass::QueryVpaVoltageListSupported() == 1
2015/03/25 11:22:37.125 CWcdmaApcClass::TesterPreSetting()
2015/03/25 11:22:37.125 [GPIB] ----RCT_WCDMA_APC_PreSetting Ex----
2015/03/25 11:22:37.125 [GPIB] 0: SYSTem:PRESet3
2015/03/25 11:22:37.125 [GPIB] SYSTem:APPLication:FORMat?
2015/03/25 11:22:37.312 [GPIB] 0: "WCDMA"
2015/03/25 11:22:37.312 [GPIB] CALL:OPERating:MODE?
2015/03/25 11:22:37.312 [GPIB] 0: CALL
2015/03/25 11:22:37.312 [GPIB] CALL:OPERating:MODE FDDT;*OPC?
2015/03/25 11:22:37.468 [GPIB] 0: 1
2015/03/25 11:22:37.468 [GPIB] CALL:OPERating:MODE?
2015/03/25 11:22:37.468 [GPIB] 0: FDDT
2015/03/25 11:22:37.468 [GPIB] ----RCT_WCDMA_AGC_PreSetting----
2015/03/25 11:22:37.468 [GPIB] CALL:CELL:POWER:SAMPLITUDE -90.0;*OPC?
2015/03/25 11:22:37.484 [GPIB] 0: 1
2015/03/25 11:22:37.484 [GPIB] SYSTEM:CORRECTION:SFREQUENCY 1920.00 MHZ,1980.00 MHZ,1850.00 MHZ,1910.00 MHZ,1710.00 MHZ,1785.00 MHZ,1710.00 MHZ,1755.00 MHZ,824.00 MHZ,849.00 MHZ,830.00 MHZ,840.00 MHZ,2500.00 MHZ,2570.00 MHZ,880.00 MHZ,915.00 MHZ,1749.00 MHZ,1785.00 MHZ,1710.00 MHZ,1770.00 MHZ;*OPC?
2015/03/25 11:22:37.515 [GPIB] 0: 1
2015/03/25 11:22:37.515 [GPIB] SYSTEM:CORRECTION:SGAIN -0.60,-0.60,-0.50,-0.50,-1.00,-1.00,-0.50,-0.50,-0.30,-0.30,-1.00,-1.00,-1.00,-1.00,-0.30,-0.30,-1.00,-1.00,-1.00,-1.00;*OPC?
2015/03/25 11:22:37.531 [GPIB] 0: 1
2015/03/25 11:22:37.531 [GPIB] CALL:SERVice:RBTest:RAB RMC12;*OPC?
2015/03/25 11:22:37.546 [GPIB] 0: 1
2015/03/25 11:22:37.546 [GPIB] 0: SETup:WCPower:CONTinuous OFF
2015/03/25 11:22:37.546 [GPIB] 0: SETup:WCPower:COUNt:STATe OFF
2015/03/25 11:22:37.546 [GPIB] 0: SETup:WCPower:TRIGger:SOURce IMMEDIATE
2015/03/25 11:22:37.546 [GPIB] 0: SETup:WCPower:TRIGger:DELay 25.0US
2015/03/25 11:22:37.546 [GPIB] 0: SETup:WCPower:INTerval:TIME 616.7US
2015/03/25 11:22:37.546 [GPIB] 0: SETUP:WCPOWER:TIMEOUT:STIME 5000.0MS
2015/03/25 11:22:37.546 IWcdmaInterface::IsBandSupported() band(0), ui_band_support(80)
2015/03/25 11:22:37.546 IWcdmaInterface::IsBandSupported() band(1), ui_band_support(80)
2015/03/25 11:22:37.546 IWcdmaInterface::IsBandSupported() band(2), ui_band_support(80)
2015/03/25 11:22:37.546 IWcdmaInterface::IsBandSupported() band(3), ui_band_support(80)
2015/03/25 11:22:37.546 IWcdmaInterface::IsBandSupported() band(4), ui_band_support(80)
2015/03/25 11:22:37.546 IWcdmaInterface::IsBandSupported() band(5), ui_band_support(80)
2015/03/25 11:22:37.546 IWcdmaInterface::IsBandSupported() band(6), ui_band_support(80)
2015/03/25 11:22:37.546 IWcdmaInterface::IsBandSupported() band(7), ui_band_support(80)
2015/03/25 11:22:37.546 CWcdmaApcClass::TesterChangeBandForMidChannel()
2015/03/25 11:22:37.546 [GPIB] SYSTEM:CORRECTION:SFREQUENCY 880.00 MHZ,915.00 MHZ,952.00 MHZ,960.00 MHZ;*OPC?
2015/03/25 11:22:37.609 [GPIB] 0: 1
2015/03/25 11:22:37.609 [GPIB] SYSTEM:CORRECTION:SGAIN -0.30,-0.30,-0.30,-0.30;*OPC?
2015/03/25 11:22:37.625 [GPIB] 0: 1
2015/03/25 11:22:37.625 [GPIB] ----RCT_WCDMA_APC_ChangeChannel----
2015/03/25 11:22:37.625 [GPIB] CALL:UPLink:CHANnel 2787;*OPC?
2015/03/25 11:22:37.656 [GPIB] 0: 1
2015/03/25 11:22:37.656 CWcdmaApcClass::StartPaControlLevelCalibration()
2015/03/25 11:22:37.656 CWcdmaApcClass::StartPaControlLevelCalibrationByIndex()
2015/03/25 11:22:37.656 CWcdmaApcClass::GetPrfByPaOctLevelControlIndex(): Band: 7, PA Control Index: 7, PRF: 24
2015/03/25 11:22:37.656 [GPIB] ----RCT_WCDMA_APC_ChangeExpectedPower----
2015/03/25 11:22:37.656 [GPIB] 0: CALL:MS:POWER:TARGET:AMPLITUDE 24
2015/03/25 11:22:37.656 CWcdmaApcClass::GetPaModeByPaOctLevelControlIndex(): Band: 7, PA Control Index: 7, PA Mode: 0
2015/03/25 11:22:37.656 CWcdmaApcClass::GetPrfByPaOctLevelControlIndex(): Band: 7, PA Control Index: 7, PRF: 24
2015/03/25 11:22:37.656 CWcdmaApcClass::GetPaGainByPaOctLevelControlIndex(): Band: 7, PA Control Index: 7, PA Gain: 1089
2015/03/25 11:22:37.656 CWcdmaApcClass::GetPaModeByPaOctLevelControlIndex(): Band: 7, PA Control Index: 7, PA Mode: 0
2015/03/25 11:22:37.656 CWcdmaApcClass::GetPrfByPaOctLevelControlIndex(): Band: 7, PA Control Index: 7, PRF: 24
2015/03/25 11:22:37.656 CWcdmaApcClass::SampleTxPowerPaCal()
2015/03/25 11:22:37.656 CWcdmaApcClass::SampleTxPower() Band: 7, UARFCN: 2787, PA MODE: 0, TPC Index: 0, Trigger Type: 0, Trigger Delay: 100ms
2015/03/25 11:22:37.656 CWcdmaApcClass::DutTx()
2015/03/25 11:22:37.765 [GPIB] ----RCT_WCDMA_APC_Initiate----
2015/03/25 11:22:37.765 [GPIB] 0: INITiate:WCPower
2015/03/25 11:22:37.968 [GPIB] INITiate:ON?
2015/03/25 11:22:37.968 [GPIB] 0: WCP
2015/03/25 11:22:37.968 [GPIB] ----RCT_WCDMA_APC_FetchResult----
2015/03/25 11:22:37.968 [GPIB] Fetch:WCPower:POWer?
2015/03/25 11:22:37.968 [GPIB] 0: +2.66546100E+001
2015/03/25 11:22:37.968 [GPIB] FETCh:WCPower:INTegrity?
2015/03/25 11:22:37.968 [GPIB] 0: +0
2015/03/25 11:22:37.968 CWcdmaApcClass::SampleTxPower() = 26.654610
2015/03/25 11:22:38.062 CWcdmaApcClass::PowerTrackingTerminated()
2015/03/25 11:22:38.062 CWcdmaApcClass::SetPaGainByPaOctLevelControlIndex(): Band: 7, PA Control Index: 7, PA Gain: 1221
2015/03/25 11:22:38.062 CWcdmaApcClass::SetOctLevelPaControlRuntimeToTarget(): Band: 7
2015/03/25 11:22:38.062 CWcdmaApcClass::SampleTxPowerPaCal()
2015/03/25 11:22:38.062 CWcdmaApcClass::SampleTxPower() Band: 7, UARFCN: 2787, PA MODE: 0, TPC Index: 0, Trigger Type: 0, Trigger Delay: 100ms
2015/03/25 11:22:38.062 CWcdmaApcClass::DutTx()
2015/03/25 11:22:38.171 [GPIB] ----RCT_WCDMA_APC_Initiate----
2015/03/25 11:22:38.171 [GPIB] 0: INITiate:WCPower
2015/03/25 11:22:38.375 [GPIB] INITiate:ON?
2015/03/25 11:22:38.375 [GPIB] 0: WCP
2015/03/25 11:22:38.375 [GPIB] ----RCT_WCDMA_APC_FetchResult----
2015/03/25 11:22:38.375 [GPIB] Fetch:WCPower:POWer?
2015/03/25 11:22:38.375 [GPIB] 0: +2.52668200E+001
2015/03/25 11:22:38.375 [GPIB] FETCh:WCPower:INTegrity?
2015/03/25 11:22:38.375 [GPIB] 0: +0
2015/03/25 11:22:38.375 CWcdmaApcClass::SampleTxPower() = 25.266820
2015/03/25 11:22:38.468 CWcdmaApcClass::PowerTrackingTerminated()
2015/03/25 11:22:38.468 PA Gain (1300) exceed the max limit(1300), so set to max
2015/03/25 11:22:38.468 CWcdmaApcClass::SetPaGainByPaOctLevelControlIndex(): Band: 7, PA Control Index: 7, PA Gain: 1300
2015/03/25 11:22:38.468 CWcdmaApcClass::SetOctLevelPaControlRuntimeToTarget(): Band: 7
2015/03/25 11:22:38.484 CWcdmaApcClass::SampleTxPowerPaCal()
2015/03/25 11:22:38.484 CWcdmaApcClass::SampleTxPower() Band: 7, UARFCN: 2787, PA MODE: 0, TPC Index: 0, Trigger Type: 0, Trigger Delay: 100ms
2015/03/25 11:22:38.484 CWcdmaApcClass::DutTx()
2015/03/25 11:22:38.593 [GPIB] ----RCT_WCDMA_APC_Initiate----
2015/03/25 11:22:38.593 [GPIB] 0: INITiate:WCPower
2015/03/25 11:22:38.796 [GPIB] INITiate:ON?
2015/03/25 11:22:38.796 [GPIB] 0: WCP
2015/03/25 11:22:38.796 [GPIB] ----RCT_WCDMA_APC_FetchResult----
2015/03/25 11:22:38.796 [GPIB] Fetch:WCPower:POWer?
2015/03/25 11:22:38.796 [GPIB] 0: +2.22988600E+001
2015/03/25 11:22:38.796 [GPIB] FETCh:WCPower:INTegrity?
2015/03/25 11:22:38.796 [GPIB] 0: +0
2015/03/25 11:22:38.796 CWcdmaApcClass::SampleTxPower() = 22.298860
2015/03/25 11:22:38.875 CWcdmaApcClass::PowerTrackingTerminated()
2015/03/25 11:22:38.875 CWcdmaApcClass::SetPaGainByPaOctLevelControlIndex(): Band: 7, PA Control Index: 7, PA Gain: 1295
2015/03/25 11:22:38.875 CWcdmaApcClass::SetOctLevelPaControlRuntimeToTarget(): Band: 7
2015/03/25 11:22:38.890 CWcdmaApcClass::SampleTxPowerPaCal()
2015/03/25 11:22:38.890 CWcdmaApcClass::SampleTxPower() Band: 7, UARFCN: 2787, PA MODE: 0, TPC Index: 0, Trigger Type: 0, Trigger Delay: 100ms
2015/03/25 11:22:38.890 CWcdmaApcClass::DutTx()
2015/03/25 11:22:39.000 [GPIB] ----RCT_WCDMA_APC_Initiate----
2015/03/25 11:22:39.000 [GPIB] 0: INITiate:WCPower
2015/03/25 11:22:39.203 [GPIB] INITiate:ON?
2015/03/25 11:22:39.203 [GPIB] 0: WCP
2015/03/25 11:22:39.203 [GPIB] ----RCT_WCDMA_APC_FetchResult----
2015/03/25 11:22:39.203 [GPIB] Fetch:WCPower:POWer?
2015/03/25 11:22:39.203 [GPIB] 0: +2.52748700E+001
2015/03/25 11:22:39.203 [GPIB] FETCh:WCPower:INTegrity?
2015/03/25 11:22:39.203 [GPIB] 0: +0
2015/03/25 11:22:39.203 CWcdmaApcClass::SampleTxPower() = 25.274870
2015/03/25 11:22:39.296 CWcdmaApcClass::PowerTrackingTerminated()
2015/03/25 11:22:39.296 CWcdmaApcClass::SetPaGainByPaOctLevelControlIndex(): Band: 7, PA Control Index: 7, PA Gain: 1300
2015/03/25 11:22:39.296 CWcdmaApcClass::SetOctLevelPaControlRuntimeToTarget(): Band: 7
2015/03/25 11:22:39.312 CWcdmaApcClass::SampleTxPowerPaCal()
2015/03/25 11:22:39.312 CWcdmaApcClass::SampleTxPower() Band: 7, UARFCN: 2787, PA MODE: 0, TPC Index: 0, Trigger Type: 0, Trigger Delay: 100ms
2015/03/25 11:22:39.312 CWcdmaApcClass::DutTx()
2015/03/25 11:22:39.421 [GPIB] ----RCT_WCDMA_APC_Initiate----
2015/03/25 11:22:39.421 [GPIB] 0: INITiate:WCPower
2015/03/25 11:22:39.625 [GPIB] INITiate:ON?
2015/03/25 11:22:39.625 [GPIB] 0: WCP
2015/03/25 11:22:39.625 [GPIB] ----RCT_WCDMA_APC_FetchResult----
2015/03/25 11:22:39.625 [GPIB] Fetch:WCPower:POWer?
2015/03/25 11:22:39.625 [GPIB] 0: +2.22573800E+001
2015/03/25 11:22:39.625 [GPIB] FETCh:WCPower:INTegrity?
2015/03/25 11:22:39.625 [GPIB] 0: +0
2015/03/25 11:22:39.625 CWcdmaApcClass::SampleTxPower() = 22.257380
2015/03/25 11:22:39.703 CWcdmaApcClass::PowerTrackingTerminated()
2015/03/25 11:22:39.703 [*Error*] PA Gain (1300) ping/pong effect detected

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